Home > Storage > PowerStore > Databases and Data Analytics > Dell PowerStore: Microsoft SQL Server Best Practices > Crash consistency and application consistency
When taking array-based snapshots of SQL Server, remember that snapshots that are taken without application coordination are considered crash consistent. Crash consistency is the storage term for data that has a snapshot taken in-flight without application awareness. While most modern applications can recover crash-consistent data, recovery can yield varying levels of success. For example, during recovery of a Microsoft Windows virtual machine, as the operating system boots, it behaves like it experienced unexpected power loss and potentially invokes check disk (chkdsk) on startup. SQL Server also contains a recovery system that uses transaction log entries to recover the database to a consistent state. Transactions that have been committed to the log are applied and those that were in-flight are rolled back.